LockHandle.cs

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// 
//  Copyright 2010-2015 Deveel
// 
//    Licensed under the Apache License, Version 2.0 (the "License");
//    you may not use this file except in compliance with the License.
//    You may obtain a copy of the License at
// 
//        http://www.apache.org/licenses/LICENSE-2.0
// 
//    Unless required by applicable law or agreed to in writing, software
//    distributed under the License is distributed on an "AS IS" BASIS,
//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//    See the License for the specific language governing permissions and
//    limitations under the License.
//

using System;

using Deveel.Data.Sql;

namespace Deveel.Data.Transactions {
    public sealed class LockHandle : IDisposable {
        private Lock[] locks;
        private int lockIndex;

        internal LockHandle(int lockCount) {
            locks = new Lock[lockCount];
            lockIndex = 0;
            IsUnlocked = false;
        }

        private bool IsUnlocked { get; set; }

        internal void AddLock(Lock @lock) {
            locks[lockIndex++] = @lock;
        }

        internal void Release() {
            if (!IsUnlocked) {
                for (int i = locks.Length - 1; i >= 0; --i) {
                    locks[i].Release();
                }

                IsUnlocked = true;
            }
        }

        public void CheckAccess(ILockable lockable, AccessType accessType) {
            for (int i = locks.Length - 1; i >= 0; --i) {
                var tableLock = locks[i];
                if (tableLock.Lockable == lockable) {
                    tableLock.CheckAccess(accessType);
                    return;
                }
            }

            throw new Exception("The given object was not found in the lock list for this handle");
        }

        public bool IsHandled(ILockable lockable) {
            for (int i = locks.Length - 1; i >= 0; i--) {
                if (locks[i].Lockable == lockable)
                    return true;
            }

            return false;
        }

        public void Dispose() {
            if (!IsUnlocked) {
                Release();

                // TODO: report the situation: there should not be
                //        a call to Release() at this point...

                locks = null;
            }
        }
    }
}